Hi, it's perfectly fine for a general FE shape functions to be negative at some points, that's clearly the case for quadratic http://hplgit.github.io/INF5620/doc/pub/sphinx-fem/._main_fem003.html#fem-approx-fe-fig-p2
Denis. On Saturday, May 5, 2018 at 3:11:24 AM UTC+2, Zhao Yidong wrote: > > Hi everyone! > I use fe, which is FESystem class, but I find fe.shape_value( const > unsigned int i, const Point< dim > & p ) (the document is here: > https://www.dealii.org/8.5.0/doxygen/deal.II/classFE__Poly.html#a8c769a449d25d54e756fc67cca5dd30b) > > sometimes returns a negative number which seems not right. > > The Point I send into the function locates in the reference space ( [-1, > 1]x[-1, 1] ), I also try the Point in the real space, but also get negative > numbers sometimes. > > Thanks any response! > -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
